Developing low-cost, efficient, and bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an appealing yet challenging task. Herein, for the first time, a NiS microsphere film was grown in situ on Ni foam (NiS/Ni foam) via a sulfurization reaction as an efficient bifunctional electrocatalyst for overall water splitting with superior activity and good durability. This NiS/Ni foam electrode delivers 20 mA cm⁻² at an overpotential of 158 mV for the HER and 50 mA cm⁻² at an overpotential of 335 mV for the OER in 1.0 M KOH. This bifunctional electrode also enables a high-efficiency alkaline water electrolyzer with 10 mA cm⁻² at a cell voltage of only 1.64 V, which could be promising in water splitting devices for large-scale hydrogen production.

Multifunctional MFe ₂ O ₄ (M = Mn, Co)–MoS ₂ –carbon dot nanohybrid composites were fabricated using a one-pot solvothermal method and applied for efficient Pb( ii ) removal.

Bimetallic iron–nickel sulfide nanowall arrays supported on nickel foam (Fe_11.1%–Ni₃S₂/Ni foam) could efficiently drive both the overall water and urea electrolysis.